clear

clear the terminal screen

TLDR

Clear the screen (equivalent to pressing Control-L in Bash shell)

$ clear
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Clear the screen but keep the terminal's scrollback buffer

$ clear -x
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Indicate the type of terminal to clean (defaults to the value of the environment variable TERM)

$ clear -T [type_of_terminal]
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Show the version of ncurses used by clear

$ clear -V
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SYNOPSIS

clear [-Ttype] [-V] [-x]

DESCRIPTION

clear clears your screen if this is possible, including its scrollback buffer (if the extended E3 capability is defined). clear looks in the environment for the terminal type given by the environment variable TERM, and then in the terminfo database to determine how to clear the screen.

clear writes to the standard output. You can redirect the standard output to a file (which prevents clear from actually clearing the screen), and later cat the file to the screen, clearing it at that point.

OPTIONS

-T type

indicates the type of terminal. Normally this option is unnecessary, because the default is taken from the environment variable TERM. If -T is specified, then the shell variables LINES and COLUMNS will also be ignored.

-V

reports the version of ncurses which was used in this program, and exits. The options are as follows:

-x

do not attempt to clear the terminal's scrollback buffer using the extended E3 capability.

HISTORY

A clear command appeared in 2.79BSD dated February 24, 1979. Later that was provided in Unix 8th edition (1985).

AT&T adapted a different BSD program (tset) to make a new command (tput), and used this to replace the clear command with a shell script which calls tput clear, e.g.,

/usr/bin/tput ${1:+-T$1} clear 2> /dev/null
exit

In 1989, when Keith Bostic revised the BSD tput command to make it similar to the AT&T tput, he added a shell script for the clear command:

exec tput clear

The remainder of the script in each case is a copyright notice.

The ncurses clear command began in 1995 by adapting the original BSD clear command (with terminfo, of course).

The E3 extension came later:

printf '\033[2J'

one could clear the scrollback using

printf '\033[3J'

This is documented in XTerm Control Sequences as a feature originating with xterm.

PORTABILITY

Neither IEEE Std 1003.1/The Open Group Base Specifications Issue 7 (POSIX.1-2008) nor X/Open Curses Issue 7 documents tset or reset.

The latter documents tput, which could be used to replace this utility either via a shell script or by an alias (such as a symbolic link) to run tput as clear.

SEE ALSO

tput(1), terminfo(5) This describes ncurses version 6.2 (patch 20200212).

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